I hate when people on TV shows just throw money down onto the table & leave without ever getting the check. How the hell do they know how much the bill is?

I had a friend who did that. Some of us were out to eat and he decided how much we should leave before the waitress came with the check. I refused to go until she came back. He was driving and threatened to leave but finally backed down. The money he wanted to leave wouldn't have covered the whole bill let alone the tip.